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Support unix domain sockets in -yy option

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This change extends -yy option to handle unix domain sockets:
their peer addresses will be printed, similar to inet sockets.

For a listening socket, its socket inode and socket path are printed.
For an accepted socket, its socket inode, the peer inode, and the
socket path are printed.
For a client socket, its socket inode and the peer inode are printed.

An example of a server side communication using netcat:

	$ ./strace -yy -e network nc -l -U /tmp/example.sock
	socket(PF_LOCAL, SOCK_STREAM, 0)        = 3
	setsockopt(3<UNIX:[14728348]>, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
	bind(3<UNIX:[14728348]>, {sa_family=AF_LOCAL, sun_path="/tmp/example.sock"}, 19) = 0
	listen(3<UNIX:[14728348,"/tmp/example.sock"]>, 10) = 0
	accept(3<UNIX:[14728348,"/tmp/example.sock"]>, {sa_family=AF_LOCAL, NULL}, [2]) = 4<UNIX:[14727246->14727245,"/tmp/example.sock"]>
	recvfrom(4<UNIX:[14727246->14727245,"/tmp/example.sock"]>, "INPUT\n", 8192, 0, NULL, NULL) = 6
	INPUT

An example of a client side communication using netcat:

	$ ./strace -yy -e network nc -U /tmp/example.sock
	socket(PF_LOCAL, SOCK_STREAM, 0)        = 3
	connect(3<UNIX:[14727245]>, {sa_family=AF_LOCAL, sun_path="/tmp/example.sock"}, 19) = 0
	getsockopt(3<UNIX:[14727245]>, SOL_SOCKET, SO_ERROR, [0], [4]) = 0
	INPUT
	...
	sendto(3<UNIX:[14727245->14727246]>, "INPUT\n", 6, 0, NULL, 0) = 6

* linux/unix_diag.h: New file.
* socketutils.c (send_query): Rename to inet_send_query.
(parse_response): Rename to inet_parse_response.
(unix_print, unix_send_query, unix_parse_response): New functions.
(receive_responses): Add a new argument named parser: a function for
handling protocol specific data parts of diag messages.
(print_sockaddr_by_inode): Call unix_print.
Replace NETLINK_INET_DIAG with NETLINK_SOCK_DIAG, they are equal
but NETLINK_SOCK_DIAG looks more generic.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
This commit is contained in:
Masatake YAMATO 2014-12-24 20:59:31 +09:00 committed by Dmitry V. Levin
parent f605e92365
commit 120e5dbcac
2 changed files with 153 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
linux/unix_diag.h Normal file
View File

@ -0,0 +1,24 @@
struct unix_diag_req {
uint8_t sdiag_family;
uint8_t sdiag_protocol;
uint16_t pad;
uint32_t udiag_states;
uint32_t udiag_ino;
uint32_t udiag_show;
uint32_t udiag_cookie[2];
};
#define UDIAG_SHOW_NAME 0x01
#define UDIAG_SHOW_PEER 0x04
struct unix_diag_msg {
uint8_t udiag_family;
uint8_t udiag_type;
uint8_t udiag_state;
uint8_t pad;
uint32_t udiag_ino;
uint32_t udiag_cookie[2];
};
#define UNIX_DIAG_NAME 0
#define UNIX_DIAG_PEER 2

136
socketutils.c
View File

@ -5,9 +5,16 @@
#include <linux/netlink.h>
#include <linux/sock_diag.h>
#include <linux/inet_diag.h>
#include <linux/unix_diag.h>
#include <linux/rtnetlink.h>
#include <sys/un.h>
#ifndef UNIX_PATH_MAX
# define UNIX_PATH_MAX sizeof(((struct sockaddr_un *) 0)->sun_path)
#endif
static bool
send_query(const int fd, const int family, const int proto)
inet_send_query(const int fd, const int family, const int proto)
{
struct sockaddr_nl nladdr = {
.nl_family = AF_NETLINK
@ -49,8 +56,9 @@ send_query(const int fd, const int family, const int proto)
}
static bool
parse_response(const struct inet_diag_msg *diag_msg, const unsigned long inode)
inet_parse_response(const void *data, int data_len, const unsigned long inode)
{
const struct inet_diag_msg *diag_msg = data;
static const char zero_addr[sizeof(struct in6_addr)];
socklen_t addr_size, text_size;
@ -95,7 +103,8 @@ parse_response(const struct inet_diag_msg *diag_msg, const unsigned long inode)
}
static bool
receive_responses(const int fd, const unsigned long inode)
receive_responses(const int fd, const unsigned long inode,
bool (* parser) (const void*, int, const unsigned long))
{
static char buf[8192];
struct sockaddr_nl nladdr = {
@ -132,7 +141,7 @@ receive_responses(const int fd, const unsigned long inode)
case NLMSG_ERROR:
return false;
}
if (parse_response(NLMSG_DATA(h), inode))
if (parser(NLMSG_DATA(h), h->nlmsg_len, inode))
return true;
}
}
@ -141,8 +150,119 @@ receive_responses(const int fd, const unsigned long inode)
static bool
inet_print(int fd, int family, int protocol, const unsigned long inode)
{
return send_query(fd, family, protocol)
&& receive_responses(fd, inode);
return inet_send_query(fd, family, protocol)
&& receive_responses(fd, inode, inet_parse_response);
}
static bool
unix_send_query(const int fd, const unsigned long inode)
{
struct sockaddr_nl nladdr = {
.nl_family = AF_NETLINK
};
struct {
struct nlmsghdr nlh;
struct unix_diag_req udr;
} req = {
.nlh = {
.nlmsg_len = sizeof(req),
.nlmsg_type = SOCK_DIAG_BY_FAMILY,
.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST
},
.udr = {
.sdiag_family = AF_UNIX,
.udiag_ino = inode,
.udiag_states = -1,
.udiag_show = UDIAG_SHOW_NAME | UDIAG_SHOW_PEER
}
};
struct iovec iov = {
.iov_base = &req,
.iov_len = sizeof(req)
};
struct msghdr msg = {
.msg_name = (void*)&nladdr,
.msg_namelen = sizeof(nladdr),
.msg_iov = &iov,
.msg_iovlen = 1
};
for (;;) {
if (sendmsg(fd, &msg, 0) < 0) {
if (errno == EINTR)
continue;
return false;
}
return true;
}
}
static bool
unix_parse_response(const void *data, int data_len, const unsigned long inode)
{
const struct unix_diag_msg *diag_msg = data;
struct rtattr *attr;
int rta_len = data_len - NLMSG_LENGTH(sizeof(*diag_msg));
uint32_t peer = 0;
size_t path_len = 0;
char path[UNIX_PATH_MAX + 1];
if (diag_msg->udiag_ino != inode)
return false;
if (diag_msg->udiag_family != AF_UNIX)
return false;
for (attr = (struct rtattr *) (diag_msg + 1);
RTA_OK(attr, rta_len);
attr = RTA_NEXT(attr, rta_len)) {
switch (attr->rta_type) {
case UNIX_DIAG_NAME:
if (!path_len) {
path_len = RTA_PAYLOAD(attr);
if (path_len > UNIX_PATH_MAX)
path_len = UNIX_PATH_MAX;
memcpy(path, RTA_DATA(attr), path_len);
path[path_len] = '\0';
}
break;
case UNIX_DIAG_PEER:
if (RTA_PAYLOAD(attr) >= 4)
peer = *(uint32_t *)RTA_DATA(attr);
break;
}
}
/*
* print obtained information in the following format:
* "UNIX:[" SELF_INODE [ "->" PEER_INODE ][ "," SOCKET_FILE ] "]"
*/
if (peer || path_len) {
tprintf("UNIX:[%lu", inode);
if (peer)
tprintf("->%u", peer);
if (path_len) {
if (path[0] == '\0') {
char *outstr = alloca(4 * path_len - 1);
string_quote(path + 1, outstr, -1, path_len);
tprintf(",@%s", outstr);
} else {
char *outstr = alloca(4 * path_len + 3);
string_quote(path, outstr, -1, path_len + 1);
tprintf(",%s", outstr);
}
}
tprints("]");
return true;
}
else
return false;
}
static bool
unix_print(int fd, const unsigned long inode)
{
return unix_send_query(fd, inode)
&& receive_responses(fd, inode, unix_parse_response);
}
/* Given an inode number of a socket, print out the details
@ -153,7 +273,7 @@ print_sockaddr_by_inode(const unsigned long inode, const char *proto_name)
int fd;
bool r = false;
fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_INET_DIAG);
fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);
if (fd < 0)
return false;
@ -166,6 +286,8 @@ print_sockaddr_by_inode(const unsigned long inode, const char *proto_name)
r = inet_print(fd, AF_INET6, IPPROTO_TCP, inode);
else if (strcmp(proto_name, "UDPv6") == 0)
r = inet_print(fd, AF_INET6, IPPROTO_UDP, inode);
else if (strcmp(proto_name, "UNIX") == 0)
r = unix_print(fd, inode);
} else {
const int families[] = {AF_INET, AF_INET6};
const int protocols[] = {IPPROTO_TCP, IPPROTO_UDP};